Seiko Cal. 6640 - 139

The Seiko 6640-139 represents an important milestone in Seiko's 1989 lineup. Powered by the 6640 caliber with 17j jewels beating at 36,000 bph, it delivers a 38 hours power reserve. [seikata-wm-13d40d9806c4]

Also known as: Monster

Specifications

Movement

Quartz

Case Material

Two-Tone

Case Width

35mm

Case Thickness

10.3mm

Lug Width

20mm

Crystal

Acrylic

Bezel

Coin-Edge

Water Resistance

120m

Dial Color

Black

Jewels

17j

Frequency

36,000 bph

Power Reserve

38 hours

Year

1989

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